Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer in the United States and the fifth-leading cause of cancer-related death in women in the United States. An estimated 22,280 new cases were detected and 15,500 deaths occurred in the US in 2012. When diagnosed early (Stages I/II), treatment is generally successful, with a five-year survival rate of up to 90%. Unfortunately, most cases are not detected until after the cancer has spread, resulting in a dismal five-year survival rate for patients with advanced disease (stages III and IV) of 30% or less. The high mortality rate of ovarian cancer is due largely to the lack of effective screening tests for early detection or diagnosis of EOC.
Current screening methods for ovarian cancer typically use a combination of pelvic examination, transvaginal ultrasonography, and assays for protein biomarkers, such as serum cancer antigen 125 (CA-125). CA125 is recognized as a poor protein biomarker for early detection due to its high false positive rate and poor sensitivity and specificity. Assays for human epididymis protein-4 (HE4), or multivariate OVA1 are only approved for monitoring disease recurrence, therapeutic response, or for use in managing women with an ovarian adnexal mass.
A recently completed study comparing many of these protein biomarkers showed that none of them performed better than CA125 as a biomarker for ovarian cancer. A few groups also have used panels of biomarkers and obtained better sensitivity and specificity than CA125 alone when used in diagnostic samples. However, a recent study found that available biomarker panels did not outperform CA125 when used in prediagnostic samples.
Compositions and methods are urgently needed to diagnose early-stage EOC with high sensitivity and specificity and for clinical management of the disease after initial diagnosis.